The present invention relates generally to a foldable portable phone (which includes a personal digital cellular (“PDC”) and a personal handy phone system (“PHS”)), and another mobile communication terminal, which are generically referred to as “mobile radio communication apparatus” in the instant application, and more particularly to an internal structure of its hinge part.
Recent widespread mobile radio communication apparatuses, such as PDCs, have roused various demands including operational comfortableness and safety, apparatus's versatility and smaller housing, etc. in addition to mere communications.
In general, there are two types of portable phones, i.e., foldable portable phones and non-foldable, rod-shaped portable phones. The foldable portable phones typically include a movable part that contains a liquid crystal display (“LCD”) screen, a fixed part that contains a ten-key, and a hinge part that connects them foldably. Some foldable portable phones include a free stop function, a one touch opening function, and a safety-improving oil damper (see, for example, Japanese Patent Applications, Publications Nos. 2002-344597, 2001-165144, 2001-177266, and 10-65778). For the apparatus's versatility, there have been proposed the camera function and Internet access function that allows a user to access the Internet to download Web information and motion-picture information.
The free stop function is one that maintains an arbitrary angle between the movable part and the fixed part. The one touch opening function is one that automatically opens the movable part when a push button on the fixed part is pressed. The oil damper is such a damper as stores oil in a hinge part's case, and uses oil's viscosity to absorb vibrations when the movable part opens.
However, these conventional portable phones do not sufficiently satisfy the operational comfort and safety to both call and non-call functions.
For example, in the call operation, the best angle for calling (referred to as the “best call angle” hereinafter) is ergonomically between the movable part and the fixed part is between about 160° and about 170°. When the angle between the movable part and the fixed part is smaller than the best call angle, the user should manually increase the angle to the best call angle.
In this respect, Japanese Patent Application, Publication No. 2001-165144 describes, at its paragraph no. [0034], a call at an opening angle state of about 145° using the one touch opening function. However, indeed a user must manually open the angle to the best call angle and two opening actions lowers the operability and require a long time to prepare for a call. Japanese Patent Application, Publication No. 2001-177266 similarly uses the one touch opening mechanism to open the housing up to 20° and then requires a manual opening up to 165°, lowering the operability, as described at its paragraph nos. [0014] and [0015].
On the other hand, Japanese Patent Applications, Publication Nos. 2002-344597 and 10-65778 disclose a one touch opening function that opens the housing up to the best call angle in a non-stop motion. However, when the opening angle in a non-stop motion is set to the best call angle as in these references, the reaction or kick in the opening is so large that it causes a safety problem, for instance, the housing undesirably jumping off from the user's palm. In addition, Japanese Patent Application, Publication No. 10-65778 particularly attaches the push button for the one touch opening mechanism to the movable part as in its FIG. 11, and allows the fixed part to open by its own weight. Since the user usually enters a telephone number while holding the fixed part during the transmission, a switch of the hand from holding the movable part to holding the fixed part after opening deteriorates the operability.
Thus, the one touch opening mechanism having excellent operational comfort and safety has not yet been proposed.
In addition, due to the recent demands for multiple functions, such as a camera function and an Internet function, a user needs to view motion and still pictures while placing the cellular phone on the desk or another location at a desired opening angle, and to take a picture while maintaining the predetermined opening angle or at a desired camera angle. Therefore, the free stop mechanism is needed for the versatility.
As discussed, in order to meet the recent demands for improved multifunction cellular phones, it is necessary to provide a cellular phone that has a one touch opening function that opens the housing to the best call angle at the calling time and a free stop function for a non-call function. In addition, it is necessary to maintain the small size of the cellular phone with these functions. For example, it is an undesirable arrangement of an engagement/disengagement mechanism coupled with a push button of the one touch opening mechanism, as in Japanese Patent Application, Publication No. 2001-165144, when the engagement/disengagement mechanism is separately provided from a forcing mechanism that opens the movable part from the fixed part and is located at a different position from that of the forcing mechanism, because this arrangement undesirably enlarges the size of the housing.